Signaling by electromagnetic waves.



/000' 000 [ll U I nil-706,746] I Patented Aug. I2, I902. Y

B. A. FESSENDEN.

SIGNALING BY ELECTROMAGNETIC WAVES. I

(Applicatibn filed .1615; 1, 1902. (No Model.) I

IIHIICI wrruesses:

UNITED STATES PATENT OFFICE.

REGINALD J\. FESSENDEN, ()F MANTEO, NORTH CAROLINA.

SIGNALING BY 'ELEQTRO MAG N ETIC- waves.

SPECIFICATION forming part of Letters Patent No. 706,746, dated August1'2, 1902- Application filed July 1, 1902. Serial No. 113,970. (Nomodel.) i

To all whom, it may concern/.-

Be it known that 1, REGINALD A. FESSEN- IDEN, a citizen of the UnitedStates, residing at Manteo, in the county of Dare and State of NorthCarolina, have invented or discovered certain new and usefulImprovements in Signaling by Electromagnetic Waves, of whichimprovements the following is a specification.

My invention relates to the transmission of power and signals byelectromagnetic waves of a kind which have been discovered andinvestigated by me, and is particularly concerned with means for theefiicient sending and receiving of such waves and for the exactmaintenance of tuning. These waves difier from those described by Hertzin that they are not complete waves, but only half-waves, and in thatthey travel over the surface of a conductor, and hence, unlike Hertzwaves, can be deflected from a straight line. They have the property incommon with Hertz waves in that the-energy received by a given areavaries inversely as a; given distance. They diifer from the wavesinvestigated by Lodge in that they are not current waves, but .s'emifreeother waves. Thus in the Lodge waves the electric energy is maximum"when the magnetic energy is minimum and allenergy not absorbed byresistance losses is recoverable, while withthe form investigated by methe electric energy is a maximum at the same time as the magnetic andnone of the energy radiated is recoverable except'by reflection. I havefound that it is essential for the proper sending-and receipt of thesewaves that the surface over whichthey are to travel should be highlyconducting, more especially in the neighborhoodof the pointwhere thewaves are generated. I have found that this highlyconducting portion ofthe surfaceshould preferably extend to atleast a. distancefrom theorigin equal to'a quarter wave length of the wave in' airand in thedirection toward the station or, stations to which it is desired Wherethe sending-stawaves may be cut off by high buildings or hightre'es,this highly-condnctin g path should 50 be extended still fartheruntil it passes beyond the limits of .the obstacle, and there thehighly-conducting portion, which may be in the form of a strip of metalor other-conductor or of a number of wires,.is connected to ground. Thisarrangement may be called a wave-chute.

In the accompanying drawings, forming a part of this specification,Figure 1 shows the artificial ground or wave-chutearranged for a stationlocated in a city. Fig. 2 .isa plan view of the arrangement shown inFig. 1, and Fig. 3 illustrates the ground or chute in connection with alow conductor, and Fig. 4 is a plan view showing arrangement of stationon rocky shore or other non-conducting ground.

In the practice of my invention I connect the grounded end of thesending or receiving conductor 1 directly or by ineans of a conductor toa-number of wires orstrips 2, radiating -out, as shown, preferably to adistance of a quarter wave length or beyond or to points beyond the highbuildings or other obstacle, as if the wires do not extend for a quarterwave length there is not sufficient capacity'between thesending-conductor and the artificial ground. These wires are grounded,preferably, at their ends and are laterally connected by. other wires orstrips 3, as shown. electromagnetic waves of such frequencies as arecommonly used to a conductor formed of a solid strip of metal. When itis desired to send one (particular direction or directions, these wires,or strips are arranged so as to lie only in the'direction in which it isdesired to send. Fig. 1 shows suchanarrangement for sending from-astation in a city having tall buildings containin g pipes or c0nduc--tors of metal.

In using a low conductorin connection with an artificial ground orwave-chute it is preferredto employ the embodiment shown in Fig. 3 ofthe conductor described and claimed in application Serial No. 62,303.This construction consists ofa tubular conductor 1*, immersedin a mediumhaving an electrical constant on which the wave length depends of avalue greaterthan that of air-as, for 'example, water, which iscontained in a vessel 5' 4, formed of conductin'g'material, as. metal.To prevent evaporation of the water, the ves- S91 is covered withglass-or other insulating This arrangement is equivalent for material,or oil may be plaee'd on the surface of the water for the same purpose.It is preferred to arrange the'sparking terminals 5 and 6 within thetubular conductor 1, one of the terminals, as 5. being electricallyconnected by an arm 7 to the conductor 1, while the terminal 6 iselectrically connected by the post 8 to the containing vessel l. end of.the tubular conductor is closed by a plug 9, of insulating material,through which passes the post 8. By securing the plug to 'the conductorand to the post 8 the latter will serve as a support for the conductor.As shown, one of the sparking terminals, as 5, is connected to thesecondary coil of a suitable generator, as the induction-coil 10, andthe other terminal, as 6, is also connected to such secondary coilthrough the post 8 and the wall of the containing vessel 4. Thecontaining vessel is connected to ground by the artificial ground orchute extending in the direction it-is desired to signal. Another veryimportant function of th construction here described is that it en-'ables the capacity and self-induction of the sending-station tobe-maintain-ed constant. which is of fundamental importance in workingtuned circuits; It frequently happens that stations are situated'onrocky portions of coast where salt spray sometimes dashes up and rendersportions of the ground-sun face near the station conducting which werepreviously insulating, hence changing thecapacity and inductance of thesending-conductor. If, however, the surface be covered by the network orstrips heretofore described, the capacitywill not be changeable, .butconstant, as the surface near the station is maintained in a constantlyconducting state.

Hence the stations once tuned will not be put The lower rated with saltwater in stormy weather and to become conductors capable of absorbingthe electromagneticwaves, thereby cutting olf a portion at least of theelectromagnetic waves from the receiving-conductor. wire guys would ingeneral absorb the waves rapidly, since for cheapness they would beThese.

inade of iron or steel, and since the currents generated'in iron orsteel conductors at such frequencies as would be used in practice areconfined to a very thin film or the outside of the wires they wouldoppose large resistance to such currents. I therefore for the fullpractice of my invention to prevent such ablsorption cover such waves,wire ropes, or chains with a coating of a non-magnetic conductor,preferably zinc or lead, and thus renfier the ohmic resistance of thewires, wire tropes, or-chains to the currentslproduced byelectromagnetic waves of the frequencies used so low that there islittle absorption. I also prefer to insulate them from ground, so thatthey have a natural period as far removed as possible from that of theelectromagnetic waves used for signaling. When a metallic mast is used,it also should have its outer surface formed of non-magnetic goodconducting material. v

- An additional advantage consequent on the employment of an artificialground or wavechute is the possibility of guarding against outsideinterference by insulating or cutting out the artificial ground in thedirection of the distributing-stationas, for example, in

the arrangement shown in Fig. 4, where the artificial ground orwave-chute is shown extending entirely around the conductor or station.The portion of network or wires 2 between the points a and 1) toward thedistributing-station X are insulated from the ground, and aconducting-path 12 is formedaround the artificial ground, extendingbetween the points a and b, so that electrical disturbances from thestation X will be led around the sort ductor or station. i p

In order to render'it certain that the natural period of the mast andguys is different from that of the electromagnetic waves, said mast andguys may be wrapped or encircled with one or more coils or turns 18 ofiron strips or wire, preferably insulated, thus increasing theinductance and natural period of the mast and guys and permitting theemployment of conducting material-e. 9., iron or 'steel-in the masts andguys. As shown in Fig. 1, the coils or turns may be either formedlocally 1:. 6., extending a short distance along the mast or guys-andsuch coils or turns may extend continuously along such parts.

While the coating of'the mast and guys with non-magnetic material neednot necessarily be used with the coils or turns, it is preferred in mostcases to both coat the masts and guys with non-magnetic material and -toalso employ the coils or turns of magnetic wire or strips, which may beformed of nickel or other magnetic material. No. 40 Brown & Sharpe gageof wire is a size suitable for the purpose.

I claim herein as my invention- 1: In a system for the transmission ofenergy by electromagnetic waves, a sendingconductor for radiating suchwaves and an artificial ground connected to the lower end of thesending-conductor and to ground and extending outwardly fromthesending-conductor, substantially as set forth.

2. In a system for the transmission of energy by electromagnetic waves,a sendingconductorrfor radiatingsuch waves and an artificial groundconnected to the lower end of the sending-conductor and to ground andextending outwardly from the sending-conductor a distance equal to aquarter wave length in air of the electromagnetic-wave length used,substantially as set forth.

3. In a system for the transmission of energy by electromagnetic waves,a sendinging from the lower end of the conductor and connected atsuitable intervals by transverse wires or strips, substantially as setforth.

4. In a system for the transmission of energy by electromagnetic waves,a sending-.

conductor for radiating such waves and an artificial ground connected tothe lower end of the sending-conductor and to ground and extendingoutwardly from the sending-conductor a distance equal to a quarter wavelength in air of the electromagnetic-wave length used and in thedirection in which it is desired to send the waves, substantially as setforth.

5. In a system for the transmission of energy by electromagnetic waves,a sendingconductor for radiating such waves and an artificial groundconnected to the lower end of the sending-conductor and connected at itsouter end to grou nd,substan tially as set forth.

6. In a system for the transmission of energy by electromagnetic waves,a sending conductor for radiating such waves supported by a metallicconductor of low resistance to currents of the frequenciesused,substantially as set forth.

7. In a system for the transmission of en- V ergy by electromagneticwaves,a sendingconductor for radiating such waves supported by ametallic conductor, a shield for said conductor-havin g low resistanceto'currents of the frequencies used, substantially as set forth.

8. In a system for the transmission of energy. by electromagnetic waves,a sendingconductor for radiatingsuch waves supported by a metallicconduct-or havinga natural period of oscillation different from that ofthe frequencies of the electromagnetic waves used, substantially as setforth.

9. A conductor for radiating electromagnetic waves, consisting of aconductor immersed in a liquid medium having an electric constant onwhich the wavelength depends of a value greater than that of air,substannetic waves, consisting of a conductor immersed in water,substantially as set forth.

11. A conductor for radiating electromagnetic waves, consisting of ametal vessel containing a medium of the character described, a conductorimmersed in said medium and a generator, substantially as set forth.

12. A conductor for radiating electromagnetic waves, consisting of ametal vessel containing a medium of the character described, a tubularconductor immersed in the medium, sparking terminals arranged in thechamber, substantially-as set forth. a

13. In a system for the transmission of en- 'ergy' by electromagneticwaves, a sendingconductor for radiating such waves, an artificial groundconnected to the lower'end of the sending-conductor and to ground andextending outwardly from the sending-conductor, and. a second groundedconducting-strip leading around the station from that facing a source ofelectrical disturbances to the op* posite side, substantially assetforth.

. 14. In a system for transmission of energy by electromagnetic waves,asupport for a condnctor encircled by one or more turns or coils ofmagnetic forth. 4

15. In a system for transmission of energy by electromagnetic waves, asupport for a condnctor encircled by one-or more turns or coils by ironwire, substantially as setforth.

16. In a system for transmission of energy by electromagnetic waves,acond uctorin combinationwith a support therefor, said sup-.

port having a coating of non-magnetic material, substantially as setforth.

material, substantially as set 1;

17. In a system for transmission of energy 1 bination with a supporttherefor, said support having a coating of non-magnetic material andencircled by one ormore turns of magnetic material, substantially as setforth.

In testimony whereof I have hereunto set Witnesses:

DARWIN S. woLco'r'r, JOHN L. Fnn'ronnn.

- by electromagnetic waves,a conductor in com

